Yes it's works where there is EDC payment terminal available like you can use in most of the shops and even in 7-11 but since Apple Pay isn't available in Thailand so most staff will not understand what you're trying to do.
Take Impact Van from BTS Mo Chit Ext 4 right beside the escalator in the parking lot. Just 36 baht. It'll drop you right in front of the new location near Cosmo Bazaar.
Foreigners are not allowed to use GrabPay Wallet. Just like Lazada Wallet or any other Wallet service. It's not to do with company policy but it's a govt policy to reduce fraud. If you succeed in opening an account with no foreigner tag attached to it then it might work.
You can still pay online by adding your card and they have promotions sometimes when you pay with card and not cash.
yes. Many times they just close it immediately if it's a common question and tell the person to search on their own.
Sometimes people don't have time to search through the group or Google to look for answers. They might be in a hurry or in trouble and looking for someone who can provide direct answer.